In handling devices which are generally termed industry robots and automatically controlled according to a motion program, it may be necessary to provide a tool supported on a three dimensionally pivotable swivel head. As the case may be, an extensible supporting arm has rotatory parts which can be rotated by servo motors (or actuator motors) around three axes at mutual angles from 45 degrees through 360 degrees (or more). In order that the swivel head parts can be rotated rapidly, they are supported with small mass and with as low a friction as possible. Their axes are relatively weak and only designed for very small bending forces. This can especially be the case if no contact occurs between tool and the work piece to be machined (or processed). Thus, no unforseeable forces appear, as for instance, in irradiation or sand blasting installations, lacquering installations and the like.
The hinge axes at the partitioning points of the support arm, which are usually vertically bendable and at its root horizontally pivotable, can be loaded with considerably greater forces due to the greater masses and the lever length of the arm sections.
In the automotive industry where such handling devices are utilized as lacquering robots, the swivel head carries a tool such as a lacquer spraying device. Further, the doors as well as motor hoods and trunk lids have to be opened prior to the lacquering or painting of the blank automobile body in order to obtain a satisfactory covering of the edge.
In already extensively automated lacquering or painting stations, relatively simple handling devices are specially provided and used to grip the doors and hoods to be opened and bring them into the desired position, in which they are maintained by further means during the subsequent lacquering (or painting) process. The considerable mechanical expense for this auxiliary activity is undesirable.
Already known from the DE-OS 32 44 053 (German document open for inspection) is a robot serving for the automatic color coating of automobile bodies of a type in which the gripping member is a door gripper for the opening and closing of the vehicle doors before and after the lacquering or painting process. The horizontal swinging of the doors does not require great forces. Since, however, the door gripper of the known robot is affixed to an actuating part provided also for the rotating of the lacquer spraying device, it could not be used for the lifting of the relatively heavy vehicle hoods because the rotating axis of the activating part could be damaged by the weight of the hood. Therefore, just as before, the above mentioned auxiliary robots are necessary.
The invention is based on the problems described. An industry robot, which besides its function proper of lacquering or other kind of treatment of work pieces, is in a position to lift automatically and without considerable additional mechanical expense, relatively heavy work pieces parts such as in particular the hoods of automobile bodies.
This problem is solved by the subject invention industry robot.